Semi-volatile trace metals (e.g., Cd, Sn, Pb, Zn, Cu, Mo) have been analyzed by using laser ablation ICP-MS in a number of silicate glasses (GSE-1G, GSD-1G, NIST 610, NIST 612, BCR-2G, BHVO-2G). Our work investigates and highlights sources of uncertainty in the analysis of semi-volatile metals using LA-ICP-MS. We identify...
The detection of subtle variations in mineral chemistry in zoned hydrothermal
alteration associated with the formation of porphyry copper deposits by short-wave
infrared spectroscopy and rock chemistry are potentially valuable vectoring tools for
mineral exploration. In order to correctly interpret the data collected by these methods,
results must be calibrated...
This study is an effort to characterize the magma sources, plumbing system, and eruptive behavior of Mount Hood, a low-explosivity recharge-dominated volcano in the Oregon Cascades. The three manuscripts in this dissertation make use of melt inclusion data, phenocryst compositions, and whole rock petrology and geochemistry to build a schematic...
This dissertation combines volcanological research of three convergent continental margins. Chapters
1 and 5 are general introductions and conclusions, respectively. Chapter 2 examines the spatiotemporal
development of the Altiplano-Puna volcanic complex in the Lípez region of southwest Bolivia, a locus of a
major Neogene ignimbrite flare- up, yet the least...
The significance of geology is commonly overlooked by the general public and underrepresented in free-choice learning environments including national parks that exhibit spectacular examples of geological features and processes. Parks are a major contributor to public learning, and a key way to teach how geology influences many aspects of our...
Distributed deformation in the backarc of Cascadia is complex. Off the west coast lies the Cascadia convergent margin. East of the plate boundary, clockwise rotation of the Oregon Coast Range block with respect to stable North America influences backarc deformation, causing extensional faults in southeast Oregon, contraction folding in southeast...
Inheritance from pre-existing mantle domains and fluid and melt contributions from active subduction together produce the geochemical signatures of mantle-derived arc basalts. In this context, this work evaluates the evolution of Cascadia mantle sources by documenting the isotopic and compositional characteristics of primitive basalts along a transect across the Eocene-Oligocene...
The Cretaceous Merín aborted-rift basin of eastern Uruguay is composed of sub-alkaline Paraná-Etendeka province basaltic flows and shallow intrusives (~133 to 131 Ma), rhyolitic ignimbrites (~130 to 128 Ma) and associated mildly alkaline to alkaline intrusions and volcanic rocks (~128 to 127 Ma). Four intrusive complexes from 20 to >30...
This dissertation presents results from three studies that address major scientific questions in glacial geology and paleoclimatology for the late Pleistocene and Holocene using relatively new geochemical and statistical techniques. Each of the studies attempts to answer a longstanding question in the respective field using geochemical or statistical methods that...
The Lights Creek Stock is an 18 square kilometer copper-bearing granitoid
intrusion within the Plumas Copper Belt in the northern California Sierra Nevada. Engels
Mine, Superior Mine, and Moonlight Valley represent the main copper-mineralization in
the Lights Creek district and small prospects include the Ruby Mine, and Moonlight
Creek. The...
Understanding continental crust formation and modification is a fundamental and longstanding geologic problem. Influx of mantle-derived basaltic magma and partial melting of the crust are two ways to drive crustal differentiation. This process results in a low density upper crust and denser, more refractory lower crust, creating significant and vastly...
The interaction of magma with continental crust at convergent margins is fundamental to
understanding if and how continents grow. Isotopic and elemental data constrain the
progressive stages of development of the magmatic underpinnings of the long-lived
Aucanquilcha Volcanic Cluster (AVC), situated atop the thick continental crust of the
central Andes...
This thesis presents the results of an investigation into the measured and modeled
mass balance of the Collier Glacier, a small (0.70 km²), valley glacier located in the
Oregon Cascade Range (44° 10' N, 121° 47' W). Here we present mass-balance
measurements conducted for the 2009 and 2010 balance years...
Constraining the development, evolution, and timescales of large silicic magma systems is important to understanding the development of granite batholiths, the relationships between volcanoes and their plutonic underpinnings, and the development of the continental crust.
The ignimbrite flare up that produced the Altiplano-Puna Volcanic Complex of the Central Andes is...